Mt. Merapi is blowing its top-again. This volcano in Indonesia erupts every few years, making big trouble for the people who live close by. This hot-headed mountain also causes problems for airplanes. On November 6, Mt. Merapi's ash plume rose to 55,000 feet (16 kilometers)-way higher than airplanes usually fly. The plume also spread out 220 miles (350 kilometers) to the west and southwest.

Volcanic ash is not like ash from a forest fire. Volcanic ash is more like tiny, floating particles of broken glass. It's very bad to breathe and very hard on airplane engines. Even far from the volcano where the plume is almost invisible, volcanic ash particles can do a lot of damage.

So, if the plumes can be invisible, how do pilots know where it's safe to fly? Satellites can help. Even a thin cloud of ash reflects light differently from air and from rain clouds. With help from a computer, satellite images can highlight volcanic ash. This information is reported to air traffic controllers, who warn pilots to stay out of the broken glass!

Satellites provide other vital information for aviators. Sometimes thunder clouds suddenly overshoot their normally flat tops with a sudden updraft of turbulent air. Even though a plane is flying above the cloud, it can still get caught in a sudden pocket of turbulence and be tossed around pretty roughly. A spilled cola may be the least of a passenger's complaints!

A new kind of satellite, called GOES-R, will help even more with aviation. GOES-R stands for Geostationary Operational Environment Satellite, "R" series. NASA plans to launch the first one in 2015. The National Oceanic and atmospheric Administration (NOAA) will operate it. GOES-R will be able to help flight controllers plan safe flight paths. It will provide quick and accurate data about not only volcanic ash plumes, but also dangerous turbulence and lightning.

Play the new "Flight Controller" game at http://scijinks.gov/aviation-game, and use GOES-R's hazard maps to plan safe flight paths for your airplanes.

This article was written by Diane K. Fisher. It was provided through the courtesy of the Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California, under a contract with the National Aeronautics and Space Administration and support from the U.S. Department of Commerce National Oceanic and Atmospheric Administration.